For many industries, transportation is the single biggest cost associated with logistics. Before inventories can be scheduled or replenished, a company must know exactly what is being shipped, when it is going to arrive, and how many kinds of items to expect.
This can be accomplished by tracking personnel whose sole purpose is to execute documentation and contact available carriers to determine shipment status. However, information obtained in this way is often nothing more than a rough estimate. To speed up the exchange of business information related to freight shipments, many carriers are turning to electronic data interchange (EDI) to better track where a shipment is, when it will arrive and what it contains. By utilizing optical symbologies and standard EDI transaction sets, a carrier can track goods within the transportation path more accurately than before.
Optical symbologies are being developed rapidly. The superior characteristics of optical symbologies makes it possible to have automatic data entry. One-dimensional bar codes are ubiquitous while two-dimensional high density codes are quickly emerging. Both techniques provide, perhaps, the best mechanism in a tracking system set. To electronically transmit business information, the increasing demands from users are no longer limited to data itself. Often, specific forms along with the symbols must be transmitted. The current technology is the use of fax machines or computer modems. The technique employed is to compress image data of the form to be transmitted and uncompress the data at the destination. The problem that often occurs at the destination is that the symbols in the forms are no longer decodable due to the processing methods in use. A need has therefore been recognized for an improved method to compress a document file containing such optical symbols as much as possible for the fast transmission and efficient storage and meanwhile to guarantee the readability of the document and the symbols thereon when data are uncompressed.
The prior art discloses many approaches to data storage, compression, and transfer. For example, U.S. Pat. No. 5,134,669 discusses using an address, bar code an signature on a form See FIGS. 3, and 4). Variable data is separated from background printing by extracting information from desired areas. Compression of the document is utilized as discussed in Column 9, lines 14-35, Column 10, lines 29-46.
U.S. Pat. No. 4,020,462 discloses removal of form background information from an image for data compression. U.S. Pat. No. 4,481,665 shows a character segmentation method for reading postal codes and addresses. U.S. Pat. No. 5,091,975 discusses compression of a signature signal. U.S. Pat. No. 5,239,625 shows merging images rasterized at different resolutions.
U.S. Pat. No. 5,040,233 discloses discarding data in a compression scheme. U.S. Pat. No. 5,134,669 to Koegh discloses the use of compression and overlayment techniques relating to executed form documents such as standardized tests, census information or surveys. This patent discloses the recognition and decoding of decodable symbols such as Postnet or bar codes placed on such forms, with the symbols being read, compressed, and subsequently overlaid upon the form indicia if needed.
Although the above-referenced prior art includes some advantages, disadvantages still exist, and the industry always welcomes new means for efficiently storing and transferring significant amounts of data.